1. Field of the Invention
The present invention relates to a magnetic head for recording and/or reproducing a magnetic signal onto/from a magnetic recording medium and in particular to a magnetic head of yoke type having a magnetic circuit block.
2. Description of the Prior Art
Recently, in the magnetic recording medium such as a hard disc tends to increase its capacity, while increasing its recording density per unit surface. In such a situation, development of a magnetic head for recording and reproducing onto/from the recording medium having a large capacity.
Recently, as a magnetic head for such a magnetic recording medium having a large capacity, there has been used a magnetic head using a magnetoresistance effect element as a magneto-sensitive block (hereinafter, referred to as an MR head). As an MR head, there is a yoke type MR head as schematically shown in FIG. 1 including yokes 102A, 102B, and 102C and having a magnetoresistance effect element 100 and a non-magnetic body 101. This yoke type MR head is constructed in such a manner that the magnetoresistance effect element 100 serving as a magneto-sensitive block will not slide along a magnetic recording medium, which enables to obtain an excellent durability. That is, in this yoke type MR head, the magnetoresistance effect element 100 serving as the magneto-sensitive block will not be brought into contact with the magnetic recording medium which may wear the magnetoresistance effect element 100.
In this yoke type MR head, the yoke 102A is arranged so as to oppose to the yoke 102B through the non-magnetic body 102, forming a magnetic gap. Through this magnetic gap, signal magnetic field from the magnetic recording medium is taken in. Moreover, in this yoke type MR head, the magnetic field take in causes a flow of magnetic flux through the magnetoresistance effect element 100 and yokes 102A, 102B, and 102C, so as to constitute a magnetic circuit.
At this moment, in the magnetoresistance effect element 100, its magnetization direction is changed by the magnetic flux flowing through the magnetic circuit, which in turn brings about a change of resistance value. In this yoke type head, a signal magnetic field is sensed by detecting the resistance change of the magnetoresistance effect element 100. That is, this magnetoresistance effect element 100 does not detect a signal magnetic field directly but detects a magnetic field take in by the yokes 102A, 102B, and 102C.
In the aforementioned yoke type MR head, the magnetoresistance effect element 100 is arranged between the yoke 102B and the yoke 102C. That is, in this yoke type MR head, a magnetic gap is formed between the yoke 102B and the yoke 102C which form the magnetic circuit, and the magnetoresistance effect element 100 is arranged in this magnetic gap.
When the magnetoresistance effect element 100 is formed in the magnetic gap between the yoke 102B and the yoke 102C, there will arise a large magnetic resistance at the bonding portion between the magnetoresistance effect element 100 and the yoke 102B and the at the bonding portion between the magnetoresistance effect element 100 and the yoke 102C. Accordingly, in the aforementioned yoke type MR head, the magnetic flux flowing through the magnetic circuit is reduced, which lowers the detection sensitivity of the magnetoresistance effect element 100.
That is, in a conventional magnetic head, even if the magnetoresistance effect element 100 is used to cope with a high density recording, it is impossible to obtain a sufficient recording/reproduction characteristic. Thus, conventionally there has been no magnetic head which has a reduced size of magnetic circuit for a high density recording and has a sufficient recording/reproduction characteristic.